It seems to be the case that multiple presidents had to veto internal improvements bills (e.g. Monroe, Madison). I’m curious why it didn’t seem to be the case that those in favor of internal improvements (e.g. Henry Clay’s American System and its proponents) didn’t just push for a constitutional amendment to allow for such legislation as it seems on multiple occasions, this legislation tended to be vetoed?
While I do not know if a Consitutional amendment for internal improvments was attempted, I will say I would assume an amendment was never attempted because many States wouldn’t have wanted an internal improvments amendment.
The reason being is because internal improvements, say a railroad in New York or a road in Louisiana would specifically benefit that particular State where the said improvement was made at the monetary expense (think tax money from the *national* treasury) of the other States. This is one of the prime reasons why internal improvments is shot down in the Philadelphia Convention. Beyond that, that’s all I know and can say for sure. The professors will have to help you from here if my answer is unsatisfactory. Pick up professor McClanahan’s book The Foinding Fathers Guide to the Constitution as it has some pages on the debates over internal improvments in both the PC and the ratifying conventions. I believe Dr. Gutzman’s PIG to the Constitution also discuss the topic as well.
Thomas Jefferson in two of his state of the union messages and James Madison in two of his called on Congress to establish a universal network of roads, canals, and bridges. Each said in one of those messages that a constitutional amendment empowering Congress to do that would have to be ratified first. None was. Because of this, Madison in his last president act issued the Bonus Bill Veto Message, in which he explained that Congress had no such power, and so he had to veto this bill.
This last is described in my James Madison and the Making of America, and Tom Woods and I have a chapter about the Eisenhower Interstate Highway System in Who Killed the Constitution?
Why no such amendment ever was adopted is an interesting question.